In practice, labor can often be difficult to induce in women. Quite frequently, uterine contractions will occur infrequently for long periods of time before increasing to the extent that the final stages of labor begin, and birth occurs. Yet inducing labor is a fairly simple task in theory.
Essentially, labor is stimulated naturally through the production of labor-inducing hormones (oxytocin) in a pregnant woman. Once these hormones attain a certain level in the woman's bloodstream, uterine contractions will increase to the rate that the final stages of birth will occur. Thus, where the natural output of these hormones is insufficient, the problem becomes one of stimulating the woman in order to create the production of this hormone, or providing a substitute for such stimulation.
Various ways of inducing uterine contractions have been attempted. For instance, oxytocin has been intravenously introduced into the body.
Research has shown that another method that increases the production of this hormone is to gently stimulate the nipples of the breasts of the pregnant woman. This stimulation gives the effect of a baby's suckling, which enhances the hormonal output to induce labor. Manual stimulation of the nipples is considered to be more desirable by many since it generates "natural" body hormones. It also avoids the intrusive delivery of Oxytocin, which is typically administered in an intravenous drip.
In recent years, nipple stimulation has been a common practice as a means for producing uterine contractions. This stimulation produces contractions in order to: (1) perform contraction stress tests, to judge the stress on the fetus; (2) to induce labor; (3) to ripen the cervix; and (4) to manage the period of labor just before birth.
Current methods of nipple stimulation have all been manual. They consist of the application of warm soaks, such as soaking the nipples with a warm damp cloth, the direct massage of nipples with gauze, indirect manual massage of the nipples through the clothes, and even use of a breastpump. Various tests have shown that hyperstimulation of the uterus often occurs with these manual methods, sometimes accompanied by fetal distress.
In addition, potential adverse effects occur during nipple stimulation through conventional methods. First, nipple discomfort may result from the application of too much pressure on the nipples. Second, there may be milk secretion during nipple stimulation, which may be distracting to both the pregnant woman as well as the individual applying the massage. Third, blisters may occur on overstimulating the nipples through excessive pressure, such as might be inadvertently applied by a breastpump. Fourth, there may be hyperstimulation of the uterus, which can result in fetal distress.